摘要
研究航空用7475-T7351铝合金厚板晶间腐蚀及剥落腐蚀性能,并利用金相和透射电镜分析该合金的腐蚀行为。结果表明:7475铝合金无明显晶间腐蚀,剥落腐蚀程度由表层的EA级递增至心部EC级。7475铝合金厚板发生剥落腐蚀主要是由于合金为片状组织,同时晶界存在由电偶腐蚀构成的通路,晶界腐蚀产物体积膨胀产生楔入力使晶间腐蚀沿着与表面平行的方向发展并逐步演变为剥落腐蚀。再结晶程度由表层到中心逐渐降低,晶粒长宽比增加,剥落腐蚀倾向增大,导致表层到心部的剥落腐蚀程度增加。
The intergranular corrosion and exfoliation corrosion properties of 7475-T7351 aluminum alloy plate for aviation were investigated,and the corrosion behaviors of the alloy were analyzed by metallographic analysis（MA）and transmission electron microscope（TEM）.The results show that no obvious intergranular corrosion is observed,but exfoliation corrosion grade of 7475-T7351 aluminum alloy increases from EA on surface to EC in the core.The exfoliation corrosion of 7475 alloy plate is mainly because of the typical lamellar structure,and the pathway formed by galvanic corrosion on grain boundary.The expansion of grain boundary corrosion product volume produces the wedging force,makes intergranular corrosion grow along the direction in parallel with the surface,and then gradually evolves into exfoliation corrosion.The degree of recrystallization decreases gradually from the surface to center,and the grain length-to-width radio increases,which inclines to exfoliation corrosion and leads to the exfoliation corrosion grade increasing from surface to center.
出处
《材料工程》
EI
CAS
CSCD
北大核心
2017年第9期129-135,共7页
Journal of Materials Engineering
关键词
7475铝合金
晶间腐蚀
剥落腐蚀
再结晶
7475aluminum alloy
intergranular corrosion
exfoliation corrosion
recrystallization
